Background:　Although　a　large　number　of　functional　magnetic　resonance　imaging　(fMRI)　studies　have　investigated　the　neural　bases　of　empathy,　little　is　known　about　its　spatiotemporal　dynamics　or　its　modulation　by　the　level　of　friendship　between　the　observer　and　the　agent　who　is　being　hurt.　Moreover,　most　of　the　previous　studies　on　empathy　have　focused　on　empathy　for　pain　rather　than　empathy　for　positive　emotions,　such　as　happiness.　In　the　present　study,　we　addressed　this　question　by　investigating　the　spatiotemporal　brain　dynamics　of　two　different　kinds　of　empathy　(empathy　for　pain,　empathy　for　happiness)　with　a　behavioral　priming　empathy　task　involving　two　different　level　of　primes　(a　close　friend,　a　stranger).　Method/Principal　Findings:　Electrical　brain　activity　and　behavioral　data　were　analyzed　from　30　subjects　(12　males　and　18　females).　Half　of　the　subjects　performed　a　behavioral　task　on　empathy　for　pain　task　(EPT),　while　the　other　half　performed　a　behavioral　task　on　empathy　for　happiness　task　(EHT).　In　each　task,　participants　viewed　prime　photographs　of　either:　(1)　a　stranger;　or　(2)　a　close　friend(primes)　followed　by　target　photographs　showing　either　a　hand　being　hurt　(or　not;　targets　in　the　EPT),　or　a　hand　in　happy　circumstances　(or　not;　targets　in　the　EHT).　In　each　task,　participants　were　asked　to　judge　the　target　situation　and　report　whether　they　could　feel　the　pain(in　EPT)　or　the　happiness(in　the　EHT),　as　a　function　of　the　primes　i.e.,　either　from　the　close　friend＇s　or　from　the　stranger＇s　perspective.　Although　our　behavioral　results　didn＇t　reveal　any　explicit　differences　among　the　different　types　of　primes　within　each　task,　our　electrophysiological　results　showed　variations　as　a　function　of　the　primes.　First,　a　early　smaller　N110　amplitude　for　pain　was　observed　in　the　anterior　prefrontal　cortex　during　the　friend　prime　condition　compared　to　the　stranger　prime　condition.　No　similar　early　effects　were　found　for　happiness.　On　the　other　hand,　both　empathy　for　happiness　(EHT)　and　empathy　for　pain　(EPT)　elicited　later　differences.　In　the　EPT,　the　friend　prime　elicited　a　larger　late　positive　potential　(LPP)　than　the　stranger　prime.　In　the　EHT,　the　friend　prime　elicited　a　larger　N250,　a　smaller　P300,　and　a　smaller　LPP　than　the　stranger　prime.　Conclusions:　Taking　the　perspective　of　a　close　friend　(as　a　prime　stimulus)　does　have　a　dual-stage　effect　on　empathy　that　is　characterized　by　an　early　modulation　for　pain　and　later　modulations　for　both　pain　and　happiness.　The　early　differences　between　friend　and　stranger　primes　for　pain　(but　not　for　happiness)　suggest　that　empathy　for　pain　is　an　automatic　process　that　has　been　socially　learned　and　passed　among　friends.　On　the　other　hand,　the　later　differences　observed　between　stranger　and　friend　prime　suggest　that　additional　cognitive　appraisal　take　place　for　both　pain　and　happiness.　Our　results　suggest　that　it　takes　more　cognitive　attentional　efforts　to　judge　a　stranger＇s　happiness　than　a　friend＇s　happiness,　whereas　the　opposite　is　true　for　pain.　These　findings　open　new　avenues　toward　a　better　understanding　of　the　empathic　mind.